Sinoora Inc. proposes to develop an on-chip spectral domain-optical coherence tomography (SD-OCT) system for ophthalmic applications. Phase I will concentrate on demonstrating the passive optical components of the OCT system on a single chip. The passive components include a spectrometer, coupler and an interferometer. These on- chip components will then be integrated with an off-chip broadband source and detector array to demonstrate OCT functionality. In Phase II, Sinoora will also integrate the broadband source and Si detector array on the spectrometer chip to enable a complete on-chip SD-OCT optical engine in a 'memory-stick' format. The proposed optical engine can then be integrated with OCT scanner head (with light delivery and collection optics) and processing software to allow a low-cost ultra-compact SD-OCT system. The final OCT system will thus provide similar performance to current bulky OCT systems at a greatly reduced cost and size. Operating at 850 nm, Sinoora will use a silicon nitride (SiN) material platform for passive components. The on-chip technology allows integration of active components such as silicon (Si) detector array, and III-V large bandwidth light source on the same SiN chip. The on-chip technology also allows mass-manufacturability of the proposed OCT chip (both active and passives) using CMOS foundries that will greatly reduce the cost of the spectrometer. The greatly reduced size of the proposed OCT engine is due in part to the proposed multi-component integration, and Sinoora's use of it's proprietary dual-stage microresonator-based architecture to do spectroscopy. Sinoora's novel spectrometer architecture allows dramatic reduction in the size of spectrometer without compromising the resolution. The greatly reduced cost, complexity and size of the system will put the OCT technology into the hands of optometrists and general physicians for quick screening of patients in field settings. The proposed spectrometer will thus help in making quality eye care affordable and accessible to general population. The same on-chip OCT idea, when demonstrated in this proposal can, in-principle, be extended for other OCT applications such as dermatology, cardiology and dentistry. Thus, demonstration of Sinoora's proposed low-cost on-chip OCT system will likely have huge ramifications across multiple medical fields.